U.S. patent number 5,801,371 [Application Number 08/686,157] was granted by the patent office on 1998-09-01 for optical reader with independent triggering and graphical user interface.
This patent grant is currently assigned to Symbol Technologies, Inc.. Invention is credited to Simon Bard, Joseph DeVita, Robert Durst, Richard Isaac, Joel Kahn, Joseph Katz, Daniel R. McGlynn, Reuven Shapira.
United States Patent |
5,801,371 |
Kahn , et al. |
September 1, 1998 |
Optical reader with independent triggering and graphical user
interface
Abstract
A system for reading indicia such as bar code symbols having a
scanner for generating a scanning light beam directed toward a
symbol to be read; a first actuator manually displaceable from a
first position to a second position for producing a first light
beam for aiming or positioning the reader, and a second actuator
manually displaceable from a first position to a second position
for initiating a scanning beam pattern for reading the symbol. The
actuators are independently operative of each other. A detector
receives the reflected light from the symbol and produces
electrical signals corresponding to data represented by the symbol.
A graphical user interface with icons simplifies system control
functions.
Inventors: |
Kahn; Joel (Rockville Centre,
NY), Isaac; Richard (East Northport, NY), DeVita;
Joseph (Patchogue, NY), McGlynn; Daniel R. (Brooklyn,
NY), Shapira; Reuven (Plainview, NY), Bard; Simon
(Setauket, NY), Katz; Joseph (Stony Brook, NY), Durst;
Robert (East Setauket, NY) |
Assignee: |
Symbol Technologies, Inc.
(Holtsville, NY)
|
Family
ID: |
23612664 |
Appl.
No.: |
08/686,157 |
Filed: |
July 24, 1996 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
407577 |
Mar 20, 1995 |
5600121 |
|
|
|
Current U.S.
Class: |
235/472.01;
235/462.01 |
Current CPC
Class: |
G06K
7/10851 (20130101); G06K 7/10881 (20130101); G06K
17/0022 (20130101); G06K 2207/1013 (20130101); G06K
2207/1011 (20130101) |
Current International
Class: |
G06K
7/10 (20060101); G06K 17/00 (20060101); G06K
007/10 () |
Field of
Search: |
;235/462,472 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Pitts; Harold
Attorney, Agent or Firm: Kirschstein, et al.
Parent Case Text
REFERENCE TO RELATED APPLICATIONS
This application is a division of application Ser. No. 08/407,577,
filed Mar. 30, 1995, now U.S. Pat. No. 5,600,121 and is also
related to co-pending application Ser. No. 07/897,835, filed Jun.
12, 1992, and Ser. No. 08/542,517, filed Oct. 13, 1995, which is a
continuation of application Ser. No. 08/294,438, filed Aug. 23,
1994, which is a continuation of application Ser. No. 08/037,143,
filed Mar. 25, 1993 (which is a division of application Ser. No.
07/715,267, filed Jun. 14, 1991, now U.S. Pat. No. 5,235,167) and
co-pending application Ser. No. 08/268,589, Ser. No. 08/269,170,
Ser. No. 08/269,171 and Ser. No. 08/268,913, filed Jun. 30, 1994,
respectively, entitled "Multiple Laser Indicia Reader Optically
Utilizing A Charge Coupled Device (CCD) Detector And Operating
Method Therefor", "Apparatus And Method For Reading Indicia Using
Charge Coupled Device And Scanning Lens Bar Technology", "Tunnel
Scanner With Multiple Scan Units Having Multiple Light Emitters And
Optionally Utilizing A Charge Coupled Detector Or Sensor Array" and
"Method And Apparatus For Reading Two-Dimensional Bar Code Symbols
With An Elongated Laser Line".
Claims
What is claimed as new and desired to be protected by letters
patent is set forth in the appended claims:
1. A system for electro-optically reading indicia having parts of
different light reflectivity, comprising:
(a) a housing having a handle for gripping by a user's hand;
(b) scanning means within the housing for scanning an indicium to
be read, and for generating an electrical signal indicative of the
indicium; and
(c) control means for controlling the scanning means, and for
processing the electrical signal, including a graphical user
interface display on the housing and a movable positioning element
accessible to the user, said control means including means for
displaying icons and an indicating cursor on the display, said
cursor being movable over the display as the positioning element is
moved by the user to a selected one of the icons, said control
means being operative for executing a function associated with the
selected icon.
2. A system according to claim 1, wherein the handle extends along
an axis about which the user's fingers are curled, and wherein the
positioning element is within reach of the user's thumb.
3. A system according to claim 2, wherein the housing has a top
wall, and where the positioning element is mounted on the top wall
for revolving movement about the axis.
4. A system according to claim 1, wherein the means for displaying
icons includes an aim icon depicting an aiming function, a scan
icon depicting a scanning function, a deactivate icon depicting a
deactivating function, and a data transfer icon depicting a data
transferring function, each icon being independently
selectable.
5. A system according to claim 4, wherein said icons are
sequentially arranged in a row.
6. A system according to claim 1, wherein the positioning element
is manually actuatable for executing the function associated with
the selected icon.
7. A system according to claim 1, wherein the control means
includes a manually actuatable trigger for executing the function
associated with the selected icon.
8. A system according to claim 7, wherein the handle extends along
an axis about which the user's fingers are curled, and wherein the
trigger underlies at least one of said fingers, and wherein the
positioning element is within reach of the user's thumb above the
trigger.
9. A system according to claim 3, wherein the positioning element
is a trackball.
10. A method of electro-optically reading indicia having parts of
different light reflectivity, comprising the steps of:
a) gripping a handle of a housing by a user's hand;
b) scanning an indicium to be read, and generating an electrical
signal indicative of the indicium; and
c) controlling the scanning step, and processing the electrical
signal, including displaying a graphical user interface on the
housing and providing a movable positioning element accessible to
the user, said controlling step being performed by displaying,
icons and an indicating cursor, and moving the cursor by moving the
positioning element to a selected one of the icons and executing a
function associated with the selected icon.
11. A method according to claim 10, and further comprising the step
of extending the handle along an axis about which the user's
fingers are curled, and positioning the positioning element within
reach of the user's thumb.
12. A method according to claim 11, and further comprising the step
of mounting the positioning element on a top wall of the housing
for revolving movement about the axis.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention generally relates to an apparatus for and a method
of electro-optically reading indicia having parts of different
light reflectivity, for example, bar code or matrix array symbols,
and, more particularly, to optical readers having an independent
triggering capability and a graphical user interface for use in
connection with aiming and positioning of the reader, or performing
other operational functions.
2. Description of the Related Art
Various optical readers and optical scanning systems have been
developed heretofore for reading indicia such as bar code symbols
appearing on a label or on the surface of an article. The bar code
symbol itself is a coded pattern of indicia comprised of a series
of bars of various widths spaced apart from one another to bound
spaces of various widths, the bars and spaces having different
light reflecting characteristics. The readers in scanning systems
electro-optically transform the graphic indicia into electrical
signals, which are decoded into alphanumeric characters that are
intended to be descriptive of the article or some characteristic
thereof. Such characteristics are typically represented in digital
form and utilized as an input to a data processing system for
applications in point-of-sale processing, inventory control and the
like. Scanning systems of this general type have been disclosed,
for example, in U.S. Pat. Nos. 4,251,798; 4,369,361; 4,387,297;
4,409,470; 4,760,248; 4,896,026, all of which have been assigned to
the same assignee as the instant application. As disclosed in some
of the above patents, one embodiment of such a scanning system
resides, inter alia, in a hand held, portable laser scanning device
supported by a user, which is configured to allow the user to aim
the scanning head of the device, and more particularly, a light
beam, at a targeted symbol to be read.
The light source in a laser scanner bar code reader is typically a
gas laser or semiconductor laser. The use of semiconductor devices
as the light source is especially desirable because of their small
size, low cost and low voltage requirements. The laser beam is
optically modified, typically by an optical assembly, to form a
beam spot of a certain size at the target distance. It is preferred
that the cross section of the beam spot at the target distance be
approximately the same as the minimum width between regions of
different light reflectivity, i.e., the bars and spaces of the
symbol. At least one bar code reader has been proposed with two
light sources to produce two light beams of different
frequency.
The bar code symbols are formed from bars or elements typically
rectangular in shape with a variety of possible widths. The
specific arrangement of elements defines the character represented
according to a set of rules and definitions specified by the code
or "symbology" used. The relative size of the bars and spaces is
determined by the type of coding used as is the actual size of the
bars and spaces. The number of characters (represented by the bar
code symbol) is referred to as the density of the symbol. To encode
the desired sequence of the characters, a collection of element
arrangements are concatenated together to form the complete bar
code symbol, with each character of the message being represented
by its own corresponding group of elements. In some symbologies, a
unique "start" and "stop" character is used to indicate when the
bar code begins and ends. A number of different bar code
symbologies exist, these symbologies include UPC/EAN, Code 39, Code
128, Codeabar, and Interleaved 2 of 5, etc.
In order to increase the amount of data that can be represented or
stored on a given amount of surface area, several new bar code
symbologies have recently been developed. One of these new code
standards, Code 49, introduces a "two dimensional" concept for
stacking rows of characters vertically instead of extending the
bars horizontally. That is, there are several rows of bar and space
patterns, instead of only one row. The structure of Code 49 is
described in U. S. Pat. No. 4,794,239, which is herein incorporated
by reference. Another two-dimensional symbology, known as "PDF417",
is described in U.S. Pat. No. 5,304,786.
Still other symbologies have been developed in which the symbol is
comprised of a matrix array made up of hexagonal, square, polygonal
and/or other geometric shapes. Such symbols are further described
in, for example, U.S. Pat. Nos., 5,276,315 and 4,794,239. Such
matrix symbols may include Vericode, Datacode, and MAXICODE (all
trademarks of their respective owners).
In the laser beam scanning systems known in the art, the laser
light beam is directed by a lens or other optical components along
the light path toward a target that includes a bar code symbol on
the surface. The moving-beam scanner operates by repetitively
scanning the light beam in a line or series of lines across the
symbol by means of motion of a scanning component, such as the
light source itself or a mirror disposed in the path of the light
beam. The scanning component may either sweep the beam spot across
the symbol and trace a scan line across the pattern of the symbol,
or scan the field of view of the scanner, or do both.
Bar code reading systems also include a sensor or photo-detector
which detects light reflected or scattered from the symbol. The
photo-detector or sensor is positioned in the scanner in an optical
path so that it has a field of view which ensures the capture of a
portion of the light which is reflected or scattered off the
symbol. This light is detected and converted into an electrical
signal. Electronic circuitry and software decode the electrical
signal into a digital representation of the data represented by the
symbol that has been scanned. For example, the analog electrical
signal generated by the photo detector is converted by a digitizer
into a pulse or modulated digitized signal, with the widths
corresponding to the physical widths of the bars and spaces. Such a
digitized signal is then decoded, based on the specific symbology
used by the symbol, into a binary representation of the data
encoded in the symbol, and subsequently to the alpha numeric
characters so represented.
The decoding process of known bar code reading system usually works
in the following way. The decoder receives the pulse width
modulated digitized signal from the digitizer, and an algorithm,
implemented in the software, attempts to decode the scan. If the
start and stop characters and the characters between them in the
scan were decoded successfully and completely, the decoding process
terminates and an indicator of a successful read (such as a green
light and/or an audible beep) is provided to the user. Otherwise,
the decoder receives the next scan, performs another decode attempt
on that scan, and so on, until a completely decoded scan is
achieved or no more scans are available.
Such a signal is then decoded according to the specific symbology
into a binary representation of the data encoded in the symbol, and
to the alpha numeric characters so represented.
Moving-beam laser scanners are not the only type of optical
instrument capable of reading bar code symbols. Another type of bar
code reader is one which incorporates detectors based on solid
state imaging arrays or charge coupled device (CCD) technology. In
such prior art readers the sides of the detector are typically
smaller than the symbol to be read because of the image reduction
by the objective lens in front of the array or CCD. The entire
symbol is flooded with light from a light source such as lighting
light emitting diodes (LED) in the scanning device, and each array
cell is sequentially read out to determine the presence of a bar or
a space.
The working range of CCD bar code scanners is rather limited as
compared to laser based scanners and is especially low for CCD
based scanners with an LED illumination source. Other features of
CCD based bar code scanners are set forth in U.S. patent
application Ser. No. 08/041,281 which is hereby incorporated by
reference, and in U.S. Pat. No. 5,210,398. These references are
illustrative of the earlier technological techniques proposed for
use in CCD type scanners to acquire and read indicia in which
information is arranged in a two dimensional pattern.
In an attempt to enable the user readily to position the hand-held
reader so as to readily read the symbol, a variety of techniques of
aiming the laser light at the indicia are known. U.S. Pat. No.
4,835,374 describes an aiming light arrangement to assist the user
in visually locating and aiming the head at each symbol, the aiming
light being a visible non-laser light source. Although the use of a
discrete aiming light arrangement did assist the user in reliably
aiming the head at the symbol for some applications, another
system, disclosed in U.S. Pat. No. 5,117,098, used a multi-position
trigger switch in a hand-held laser scanner. The head was arranged
to be aimed at the symbol to be scanned during a first operational
state in which an aiming pattern was emitted. Once the user had
aligned the head properly with respect to the location of the
symbol, the trigger switch was actuated again to put the device
into a second operational state in which the beam was scanned
across the symbol in the normal scanning or reading mode, and the
symbol decoded. The same laser was used both to create the aiming
pattern and the scanning beam.
European Patent No. 0355355 describes a combination bar code reader
and EAS tag deactivator, including an embodiment with a
multi-position trigger.
Another bar code reader with a multi-position trigger switch (for a
rather different purpose) is disclosed in the article by Grabowski
and Wohl, an IBM Technical Disclosure Bulletin, page 78, Volume 5,
No. 5, October 1962.
Yet other aiming and scanning arrangements in which changing from
one mode to another is performed in an automatic (i.e., non-manual)
manner are described in the series of U.S. Pat. Nos. 4,933,538;
5,229,591; and 5,250,791 assigned to the present assignee.
SUMMARY OF THE INVENTION
OBTECTS OF THE INVENTION
It is a general object of the present invention to provide an
improved indicia scanner without the limitations of prior art
readers.
It is another object of the invention to provide an optical reader
with dual triggers for independently performing in any desired
order one or more of the following functions: (i) aiming; (ii)
range-finding; (iii) zooming, focusing or spot size adjustment;
(iv) image capturing; and (v) flying spot scanning.
It is a further object of the present invention to provide a
scanner for reading both two-dimensional or more complex indicia
and linear bar codes by manually activating beam or scan line
control features.
It is a still further object of the present invention to provide an
indicia scanner capable of providing the features of both a flying
spot light beam scanner and an imaging scanner in a single unit
which is trigger selectable.
It is yet another object of the invention to provide a hand-held
indicia reader that is capable of aiming or being oriented and also
imaging the field of view.
It is also an object of the invention to provide an indicia reader
capable of automatically and adaptively reading indicia of
different symbology types, including indicia comprised of a matrix
array of geometric shapes, in close spatial proximity, or at
arbitrary ranges.
It is an additional object of the invention to provide a graphical
user interface for controlling the operation of the optical
reader.
It is an even further object of the invention to provide a method
which can be used to accomplish one or more of the above
objectives.
Additional objects, advantages and novel features of the present
invention will become apparent to those skilled in the art from
this disclosure, including the following detailed description, as
well as by practice of the invention. While the invention is
described below with reference to preferred embodiments, it should
be understood that the invention is not limited thereto. Those of
ordinary skill in the art having access to the teachings herein
will recognize additional applications, modifications and
embodiments in other fields, which are within the scope of the
invention as disclosed and claimed herein and with respect to which
the invention could be of significant utility.
FEATURES OF THE INVENTION
In keeping with these objects, and others which will become
apparent hereinafter, one feature of this invention resides,
briefly stated, in an optical reader for reading indicia having
parts of different light reflectivity, e.g. two-dimensional or
one-dimensional symbols having bars and spaces, which is manually
and independently controllable, for performing one or more of the
following functions in any desired sequence: (i) aiming; (ii) range
finding; (iii) zooming, focusing or spot size adjustment; (iv)
image capturing; and (v) flying spot scanning.
It is yet another feature of the invention to provide a system for
reading coded symbols or the like having a scanner for generating a
laser beam directed toward a symbol to be read; a first trigger
operatively connected to the scanner and manually displaceable from
an off position to a first selectable position for producing a
first beam pattern for aiming or positioning the reader with
respect to the symbol, and a second trigger independently operative
relative to the first trigger and manually displaceable from a
first position to a second position for reading the symbol; and a
detector having a field of view for receiving reflected light from
the symbol to produce electrical signals corresponding to data
represented by the symbol.
Another feature of the present invention is to provide a system for
reading coded symbols on a target in a field of view, including a
scanner for scanning at least one of a laser beam and said field of
view so as to generate an electrical signal indicative of the
reflected light intensity over the field of view, and a manually
actuable switch operatively connected to the scanner and manually
displaceable from an off position to a first selectable position
for scanning the symbol and a second selectable position for
transferring the data represented by the symbol and/or activating a
process using the data in a peripheral module.
Still another feature of the invention is to provide a dual trigger
switch in a bar code reader with either or both switches being
simultaneously and independently activatable for performing an
operational function.
It is yet another feature of the invention to provide a system for
reading coded symbols or the like having a range finder within a
reading head for determining the distance from the head to the
symbol to be read, and for generating a distance signal; an
adjustable optical element positioned within the reading head; and
a control device for adjusting the optical element to focus in a
different image plane in dependence upon said distance signal.
In one embodiment of the invention, an aiming beam is provided
which enables the user to align the reader with the indicia to be
read. During this aiming mode of operation, the rangefinder
determines the approximate distance between the reader and the
indicia. Once the user has properly aligned the reader, a trigger
is pressed a second time to switch the reader into a second mode.
Alternatively, a second trigger position may be used, or a second
trigger switch, to switch to the second mode. The aiming beam is
preferably then switched off. The indicia will be imaged on a
two-dimensional light detector array.
In a second embodiment, imaging optics are adjusted both by focus
and by magnification in order to provide an optimized match of the
image of the indicia and the available area of the detector array.
Further information may be provided by the user via a keyboard
(such as the expected size of the indicia), and this information
may also be used in adjusting the imaging optics.
A device may also be provided for adjusting the illumination beam.
In particular, the size, shape or intensity of the beam may be
controlled, as may its duration, the pattern and/or the area it
covers. Once again, all of this may be determined according to the
measured distance.
An ambient light detector may be provided which determines the
ambient illumination conditions. The signal from this detector may
be used to adjust the illumination beam, thereby ensuring that the
detector is not swamped by high levels of ambient light.
Control of the device may be via a user-operable trigger, which can
be moved between a first position (representing a first operational
mode) and a second position (representing a second operational
mode). The optical reader is preferably a hand held reader, but
hands-free readers, and stationary readers are also within the
scope of the invention.
A controller, for example a microprocessor, appropriately
programmed and guided by a graphical user interface, deals with the
overall operation and control of the device.
An automatic shut-off device may be provided whereby, when the
optical reader has captured the image, and possibly decoded it, the
reader is switched off. Alternatively, the reader may automatically
return to a low-power quiescent mode.
An audio and/or visual display may be provided to advise the user
whether the current indicia has properly been decoded.
The novel features which are considered as characteristic of the
invention are set forth in particular in the appended claims. The
invention itself, however, both as to its construction and its
method of operation, together with additional objects and
advantages thereof, will best be understood from the following
description of a preferred embodiment, which is described by way of
example only, when read in conjunction with the accompanying
drawing.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a view of a bar code reader system with dual trigger
switches in a point-of-sale application environment according to
the present invention;
FIG. 2a is an enlarged top plan view of a bar code reader with a
trackball joystick) and a graphical user interface display
according to the present invention;
FIG. 2b is a perspective view of the bar code reader of FIG.
2a;
FIG. 2c is an enlarged top plan view of the display of FIG. 2a;
and
FIG. 3 is a schematic block diagram of the preferred embodiment of
the internal optical and electronic elements of the present
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The invention, in the preferred embodiment, takes the form of a
portable, hand held optical reader contained within a housing (or
body) 10 of appropriate shape. The exact form of the housing 10 is
not of importance, and may depend upon the particular application.
A conventional gun-shaped housing would be suitable in many cases.
The reader may also be arranged for hands-free use and could be
fixed instead of being portable.
In the most rudimentary implementation, the invention provides a
system for reading coded symbols with a light source for generating
a beam directed toward a symbol to be read, a detector for
receiving reflected light from the symbol to produce electrical
signals corresponding to data represented by the symbol, a first
actuator manually displaceable from an off position to a first
selectable position for initiating reading of a symbol, and an
independently operable second actuator is manually displaceable
from a first position to a second position to transfer said data
represented by the symbol. As an example, the data may be
transferred to a printer, or to a display for visually displaying
the data. The data may also be transferred to a radio frequency or
IF transmitter for wireless communication of the data to a remote
receiver.
In the point-of-sale system depicted in FIG. 1, merchandise or
articles 85 having a one-dimensional bar code symbol 14 are
arranged on a counter 87 on which the bar code reader 10 is
mounted. The articles 85 are shown placed in a shopping tote 86
which includes an RF identification (ID) tag 88. In one
application, the bar code symbols may identify the merchandise,
while the RF ID tag 88 may identify the shopper or customer. In
another application, the tote 86 may be a shipping container, and
the RF ID tag denotes the destination, routing, or shipping
address. An RF ID tag detector 69 (shown in FIG. 3) may be included
as part of the system. The system may employ both methods of
identification, as will be subsequently described.
FIG. 1 shows a bar code reader 10 capable of both stationary and
hand-held operation with dual triggers according to the present
invention. The reader housing is depicted in the shape similar to
the gun-shaped housings known in the prior art. The reader 10 may
be picked up by the user for portable use, or mounted in a stand 80
in which the reader can function operating in a fixed mode. In the
fixed mode, it is positioned to read the bar code symbol 14 on a
target within the field of view of the reader, such as a region of
the counter 87. The reader 10 may make electrical contacts to the
stand 80, which in turn may be connected to a cash register 89
and/or host computer 82 which may include elements such as a
display 83 and a printer 84. In the present invention, the handle
position 72 of the housing 10 (i.e., the portion of the housing
which is gripped by the user's hand in normal use) includes two
discrete trigger switches 70 and 71. The upper switch 70, designed
to be activated by the index finger, controls one function or
operation, while the lower switch 71, designed to be activated by
different fingers, controls a different operation, as will be
described below. The switches 70, 71 are independently operable
and, hence, either one can be operated before, after, or
simultaneously with, the other.
Alternatively, in another embodiment, a single two-position trigger
switch may be used in place of dual trigger switches. Examples of
functions that may be performed by activation of the first and
second positions of a dual or two-position trigger switches are as
follows:
1) Position One - aim; Position Two - scan.
2) Position One - scan; Position Two - EAS deactivate.
3) Position One - scan; Position Two - RF ID.
4) Position One - scan; Position Two - transfer data or operate
peripheral (e.g., printer, communication and display)
Examples of functions that may be performed with a single trigger
with three trigger positions are as follows:
1) Position One - aim; Position Two - scan; Position Three EAS
deactivate.
2) Position One - aim; Position Two - scan; Position Three - RF
ID.
3) Position One - scan; Position Two - RFID; Position Three - EAS
deactivate.
As used above, the term "EAS deactivate" refers to an operation of
deactivating an EAS tag on the article. Reference may be made to
U.S. Pat. No. 5,005,125 to describe EAS systems and tags, and their
method of deactivation, and to European Patent No. 0355355. The
term "RF ID" refers to reading an RF ID tag, such as described in
U.S. Pat. No. 4,739,328.
The sequence and operations described above are merely
illustrative, and a particular point-of-sale check-out, shipping, a
distribution system or other application may use other sequences or
combinations rather than the ones described above.
FIG. 2a illustrates the top plan view and FIG. 2b a perspective
view of the reader 10 now shown as incorporating a display 100 and
a trackball, also known as a joystick 101. The joystick may be
moved by the user's thumb to move an arrow-shaped pointer 102 or
indicating cursor on the display screen 100. As best shown in FIG.
2c, the display 100 may display icons 103 which in a particular
programming environment or graphical user interface may be used to
refer to specific program applications, documents, or data records
that may be accessed by the system. Thus, FIG. 2c shows an "AIM"
icon 103a, a "SCAN" icon 103b, a "DEACTIVATE" icon 103c, and a
"DATA TRANSFER" icon 103d. When the pointer 102 is moved among the
phantom line positions shown in FIG. 2c, and is aligned with the
desired icon, the user can select the application or document
represented by the icon by activating a switch by pressing the
joystick 101 to cause it to "click" and thereby register to the
system the selected icon as representing the particular
application, document, or data record desired to be accessed,
executed or displayed. Thus, aiming, scanning, tag deactivating and
data transfering are executed in response to selecting icons
130a-d, respectively. As examples of the type of documents which
may be displayed, two "windows" representing distinct programs P1
and P2 are displayed with the "active" or overlapping one 105
displaying data 106.
FIG. 2a and 2b also illustrate a solar cell collector 107 which
functions to power the reader and/or charge a battery contained
within the reader housing 10. In applications in which the stand 80
may be utilized in a location remote from the host computer 82 or
other power source, it is advantageous to provide separate means
for powering the reader. A solar power battery charger coupled to
the solar cell collector 107 achieves this objective in one
embodiment of the present invention.
As alternatives to the use of solar cells, microwave or heat energy
sources could also be used. In the first variant, a microwave
transmitter is installed in the close vicinity of the device (e.g.,
in the cash register around which a cordless scanner is used). This
could be either the transmitter utilized to communicate with the
portable device or one which is specific to this task. For both
cases, its frequency could be either the same as the one utilized
for the communication channel or a different one. Because of
regulatory and safety/health issues, in most practical situations
only low power levels should be generated.
Alternatively, heat generated in the device could be used, derived
from the inherent inefficiency of its components. For example if
.OMEGA..sub.1 is the device inefficiency (which results in heat
generation), and .OMEGA..sub.2 is the process efficiency of
converting heat to electricity, then a fraction of .OMEGA..sub.1
.times..OMEGA..sub.2 of the battery energy can be used for its
charging.
Thus, another feature of the present invention is to provide a
system for electro-optically reading indicia having parts of
different light reflectivity, a scanning head with a housing; a DC
voltage-powered light source mounted in the housing for generating
a light beam that may be directed toward an indicium for reflection
therefrom; a sensor for detecting light of variable intensity
reflected off the indicia and for generating a signal indicative of
the indicia; a battery in the housing for supplying DC voltage to
the light source; and a solar cell powered charger for charging the
battery in the housing.
In one embodiment of the invention, a primary battery is placed in
the device: Primary (non-rechargeable) batteries generally have
energy density larger than that of secondary batteries (e.g.,
.congruent.100 Wh/kg for an alkaline cell vs. .congruent.30 Wh/kg
for a standard Ni-Cd cell). However, this large capacity is
substantially reduced at large discharge rates. Devices that
operate in short "bursts" during the session (e.g., bar code
scanners), do create a high rate of drain on the battery. In the
preferred embodiment, the primary battery provides a substantially
small charge current to the second battery. The secondary
(rechargeable) battery is the power source which directly powers
the device, and is continuously recharged at a low level ("trickle
charge") throughout the session, while maintaining the cordless
mode of operation. The secondary battery can be used to deliver the
same overall apparent capacity to the user. In this particular
case, at the end of the session the primary battery is replaced and
the secondary battery is recharged. However, the overall
combination provides for a session which is longer than if a single
battery type were used (assuming the same total battery
weight).
The following is an illustrative example (specific values used are
approximate only). Assume that a device is powered by a 3.6 V
battery (a series combination of three 1.2 V cells) and a maximum
of 100 g is allocated for the battery. If only a primary cell is
used, then its density is 40 Wh/kg (because of the assumed high
drain rate). This will translate to a capacity of (40
Wh/kg.times.(0.1 kg)/(3.6 V)=1.11 Ah. Similarly, if a secondary
battery is used, the resulting capacity is (30 Wh/kg).times.(0.1
kg)/(3.6 V)=0.83 Ah. If a combination of 50 g primary and 50 g
secondary are used, (where the primary battery is used to trickle
charge the secondary one, and thus its higher density is achieved),
then the total capacity for this case is (100 Wh/kg).times.(0.05
kg)/(3.6 V)+(30 Wh/kg).times.(0.05 kg)/(3.6 V)=1.39 Ah+0.42 Ah=1.81
Ah, which is a substantial increase over the previous
alternatives.
The following is another illustrative example. Assume a device
which normally operates at 3 V with a 500 mAh battery in 8-hour
shifts ("sessions"). Using the concept of this invention, the
device is redesigned to operate with a 250 mAh battery. The
additional 250 mAh capacity is to be supplied via the trickle
charge. The required charging current is thus (250 mAh)/(8
hours)=30 mA. At 3 V operation, this corresponds to 90 mW. Assuming
10% power conversion efficiency of solar cells, about 900 mW of
ambient light is required to impinge upon the solar cell area. In
full sunlight, the intensity is approximately 100 mW/cm.sup.2, and
in this case a total solar cell area of 9 cm.sup.2 will be
required. Indoor operation with normal lighting conditions will
require substantially larger areas.
Turning to FIG. 3, the housing 10 has a window 12 therein, which is
arranged to be positioned by the user opposite a bar code symbol or
other indicia 14 to be read. Behind the window 12 is an
illumination source, such as a laser 16, with optics 18, an
illuminating LED or laser 20, with optics 22, and collection optics
24. Behind the collection optics 24 is a detector or a
two-dimensional imaging array 26 such as a CCD array which is
arranged to be read out by signal processing circuitry 28. Instead
of being a CCD array, the array 26 could comprise any
two-dimensional solid-state imaging device; it could, for example,
comprise a random-access device. Also provided is a detector 30
coupled to range finder circuitry 32, the purpose of which is to
automatically determine the distance d between the window 12 and
the indicia 14 which is to be read. The range finder may operate by
any desired means, such as by ultrasound or optically. There is
also an ambient illumination detector 34 which senses the ambient
illumination conditions. The solar cells 107, battery recharger
110, primary battery 111, and secondary battery 112 are also
depicted.
Operation of the device is overseen by a common microprocessor or
controller 36, operated by means of a keypad 38 and a trigger
mechanism 40. The trigger mechanism incorporates dual trigger
switches 70, 71, such as shown in FIG. 1, having first switch
contact 42 and second switch contact 44.
In use, the operator first pulls the first trigger 70 back to a
first position, in which it meets the contact 42. This causes the
controller 36 to actuate the laser 16 to produce a visible aiming
beam 46 which the operator then manually aligns with the indicia
14. The aiming beam preferably produces a static pattern, or
designation pattern, preferably a point or a line which is easily
visible. Ideally, the optical system 18 incorporates a cylindrical
lens, such as that previously described in copending U.S. patent
application Ser. No. 08/268,913 noted above in the Reference to
Related Applications, to produce a solid line of light which can
quite easily be aligned with the longitudinal axis of the bar code
symbol.
Once the operator has properly aligned the reader, the operator
then pulls the second trigger 71 which closes the contact 44. This
causes the controller 36 to instruct the range finder 32 to
determine the distance d. On the basis of that determination, and
on the basis of information provided by the ambient illumination
detector 34, the controller 36 determines the optimal focusing,
magnification and illumination parameters that will be required to
decode the image. The controller then sends signals to a focus and
magnification control mechanism 48, which adjusts the imaging
optics 24, to an illumination control 50, which adjusts the
illumination provided by the laser 20, and to a further control 52
for adjusting the optics 22, thereby adjusting the area and/or
intensity of the illuminating beam 54 which will subsequently be
produced.
Once all the parameters have been determined, and the necessary
adjustments made, the controller 36 switches off the laser 16 and
switches on the LED or laser 20 for a predetermined period, thereby
illuminating the indicia 14 with the beam 54. If the adjustments
have correctly been made, the beam will be an optimized match with
the size of the code at the measured distance d. An estimate of the
apparent size of the code, as seen from the window, can be
determined from the known actual size of the code (where
available), which may have been entered in advance by means of the
keyboard 38.
The indicia 14 is imaged onto the two-dimensional semiconductor
array 26, which is then read out by the signal processing circuitry
28. The signals are then decoded by a decoder 56. Feedback is
provided to the operator by means of a display 58 and/or audio
feedback means 60.
Once the image has been satisfactorily captured, processed and
decoded, the controller may automatically instruct the reader to
switch itself off, or alternatively to move into a low-power
quiescent mode.
In a first variation of the preferred embodiment shown in FIG. 3,
the rangefinder 32 and the detector 30 may be omitted. Instead,
determination of the distance d may be achieved by analyzing the
reflected light 62 which is returned from the symbol as it is being
illuminated by the target beam 46. For example, the beam 46 may be
pulsed, and temporal measurements may be taken to determine the
distance. Alternatively, the beam 46 may be scanned across the
indicia, in which case the spectral characteristics of the received
signal may provide some indication of the distance. Yet a further
alternative is to calculate phase relationships within the
reflected light.
A further variation is to replace the lasers 16,20 with a single
laser, and the optics 18,22 with a single set of optics. In such an
arrangement, the same laser operates to produce the aiming beam
(designating pattern) 46 and the imaging illuminating beam 54. Such
an arrangement is, of course, only of assistance where the laser
produces light of a wavelength which can easily be seen by the
operator.
Instead of the trigger 40 being a dual trigger, or two-position
trigger, it could be a multi-position trigger. The various trigger
positions could undertake a variety of functions; for example, one
trigger position might produce a first static pattern (designation
pattern), with a second position producing a second pattern, and a
third position producing the measurement illumination. This type of
arrangement could be useful where the device is to be used in a
variety of situations, or with a variety of different bar code
symbols, since it would then be possible for the operator to choose
an appropriate designation pattern for the indicia which is to be
measured. Other trigger positions of a multi-position trigger could
provide an on/off function, or other functions for controlling the
information shown on the display 58, such as deactivation of an EAS
tag, reading of an RF ID tag, or activation of a peripheral device,
such as a modem, radio, infrared transmission unit or other
communications device, or a peripheral device such as a printer.
One example would be initiating wireless communication of the data
represented by the symbol through a communication unit 113
connected to the controller 36. Different trigger positions could
also be provided to alter the measurement characteristics of the
device, for example to provide at least a certain level of manual
control over the focusing and/or magnification, such as zooming or
spot size adjustment. All of these features will, of course, be
controlled by the controller 36.
Instead of, or in addition to, the trigger 40, the aforementioned
graphical user interface depicted in FIGS. 2a, 2b and 2c, is useful
in performing system functions. Thus, as described above, the
user's thumb is used to move the joystick 101 and position the
pointer 102 on a selected icon, thereby "highlighting or selecting"
the function associated with that icon. Thereupon, either the
thumb, is used again to depress the joystick, or one of the user's
other fingers is used to depress one of the trigger switches 71 or
72, thereby "choosing or executing" the selected function.
While the preferred form of the optical reader, already described,
is a portable, hand-held device, various other options are
possible. The embodiment shown in FIG. 3 could, instead, represent
a fixed embodiment which is arranged to be built into a
point-of-sale unit, for example above a conveyor. The automatic
magnification/focus controls enable the device to deal with a
variety of different sized packages, passing along the conveyor,
thereby presenting bar code symbols at a variety of different
distances from the device.
It will be understood that each of the elements described above, or
any two or more together, also may find a useful application in
other types of constructions differing from the types described
above.
While the invention has been illustrated and described as embodied
in an optical reader having an independent triggering mechanism and
graphical user interface, it is not intended to be limited to the
details shown, since various modifications and structural changes
may be made without departing in any way from the spirit of the
present invention.
Without further analysis, the foregoing will so fully reveal the
gist of the present invention that others can, by applying current
knowledge, readily adapt it for various applications without
omitting features that, from the standpoint of prior art, fairly
constitute essential characteristics of the generic or specific
aspects of this invention and, therefore, such adaptations should
be and are intended to be comprehended within the meaning and range
of equivalents of the following claims.
* * * * *